Javier Mascherano's desperation to leave Liverpool led the Argentina captain to take a pay cut to complete his £20m move to Barcelona. The midfielder has claimed broken promises – and not his family's failure to settle on Merseyside – prompted his decision to force a move from Anfield.

The 26-year-old finally joined the Spanish champions on Monday night following a 12-month transfer pursuit plus a bitter end to his Anfield career, amid suggestions he refused to play in Liverpool's 3-0 defeat at Manchester City to secure an exit. Mascherano rejects that allegation and has denied that his main motivation for leaving Liverpool was to be reunited with his wife and young children, who have lived in Buenos Aires for most of his time on Merseyside.

Instead Mascherano, who was refused a move to Barcelona last summer but promised he could leave if Liverpool received an acceptable offer this year, and who was offered a new contract at Anfield last season, has blamed his former club for the split.

"When they started to involve my family and to say things that didn't make sense, I obviously suffered," he said. "They'd promised me something for a whole year and they never fulfilled their promise. And that didn't have anything to do with my family or anything else. When you read or hear lies, you obviously get angry."

In announcing their agreement with Liverpool last week Barcelona praised "the intensive efforts made by the club in the final hours and through the player himself in the negotiations", and it is understood Mascherano accepted less than his £70,000-a-week wage at Anfield to secure a four-year contract at the Camp Nou. The midfielder said today: "I'd also like to thank the club for their efforts. They've spent a lot of money and it was my duty to give way a bit to make this dream come true. When this chance came up I didn't hesitate. I've joined the best club in the world and the best team in the world."

Mascherano expressed his gratitude to the former Liverpool manager Rafael Benítez for rescuing him from a miserable spell at West Ham United in 2007. He said: "Rafa taught me tactics. He's one of the coaches who have taught me the most in my career and I'm very grateful to him. He was fundamental. He gave me the chance to join Liverpool. He had confidence in me at a time when, perhaps, nobody would have dreamed of giving me an opportunity. I'll be grateful to him all my life."

Liverpool's new £3.5m signing Paul Konchesky is to make his debut in Jamie Carragher's testimonial against an Everton XI at Anfield on Saturday.